This project grew out of our neurophysiological and neuroanatomical investigation of the corticocoritcal connections in the somatic sensorimotor cortex of the monkey and their role in the control of primate motor behavior. In that project we redefined three of the main cortical inputs to the primary motor cortex (MI): the premotor cortex (PM), the supplementary motor cortex (MII) and the transition zone between the motor and somatic sensory cortex, area 3a. These three cortical fields surround MI and can be differentiated from MI on the basis of neuronal responses to peripheral inputs, thresholds for evoking movements with intracortical electrical stimulation, the properties of single neurons during the performance of an operantly conditioned motor task, cytoarchitecture, and connectivity. In the past year, we have elaborated this study by an analysis of the activity of single neurons in PM during a visually guided motor task. These results support the hypothesis that PM plays a role in the execution of visually guided movements and the preparation for voluntary movements.